Intiial work on 'Singing of Plugins and Material Packages'.

Most of the work is in Uranium right now -- especially since the plugins part is picked up first, and there are already plugins at Uraniums level.

part of CURA-6856

cura/ApplicationMetadata.py

@@ -42,6 +42,11 @@ try:
 except ImportError:
     CuraDebugMode = DEFAULT_CURA_DEBUG_MODE
 
+try:
+    from cura.CuraVersion import CuraIsEnterpriseVersion  # type: ignore
+except ImportError:
+    CuraIsEnterpriseVersion = True  # (DEFAULT_CURA_BUILD_TYPE != "")
+
 # Each release has a fixed SDK version coupled with it. It doesn't make sense to make it configurable because, for
 # example Cura 3.2 with SDK version 6.1 will not work. So the SDK version is hard-coded here and left out of the
 # CuraVersion.py.in template.

cura/CuraApplication.py

@@ -719,6 +719,8 @@ class CuraApplication(QtApplication):
     ##  Handle loading of all plugin types (and the backend explicitly)
     #   \sa PluginRegistry
     def _loadPlugins(self) -> None:
+        self._plugin_registry.setCheckIfTrusted(ApplicationMetadata.CuraIsEnterpriseVersion)
+
         self._plugin_registry.addType("profile_reader", self._addProfileReader)
         self._plugin_registry.addType("profile_writer", self._addProfileWriter)